VETERINARY HELMINTHOLOGY AND ENTOMOLOGY

Transcription

1 VETERINARY HELMINTHOLOGY AND ENTOMOLOGY THE DISEASES OF DOMESTICATED ANIMALS CAUSED BY HELMINTH AND ARTHROPOD PARASITES BY H. O. MONNIG, B.A., DR.PHIL., B.V.Sc. PROFESSOR OF PARASITOLOGY, FACULTY OF VETERINARY SCIENCE, UNIVERSITY OF PRETORIA; VETERINARY RESEARCH OFFICER, ONDERSTEPOORT, SOUTH AFRICA SECON DEDITION BAILLIERE, LONDON TINDALL 7 & 8 HENRIETTA STREET, COVENT GARDEN, w.e

2 XIV CONTENTS PHTLUM ARTHROPODA SECTION IV ARTHROPOD PARASITES CLASSIFICATlON-MoRPHOLOGy-DEVELOPMENT A. DIRECTLY POISONOUS ARTHROPODA PAGES :J Myriapoda-,-Insecta: Piercing or biting forms; stinging insects; nettling forms; cryptotoxic forms. Scorpions. Solpugida-Araneida-C. Acarida: Mites in foodstuffs B. ARTHROPODA AS PARASITES AND TRANSMITTERS OF DISEASE.GLASS INSECTA Order ORTHOPTERA COCKROACHES Order COLEOPTERA Order DlPTERA - Sub-Order 0 r tho r r hap h a Family CHIRONOMIDJE: Culicoides-Ceratopogon Family SIMULIIDJE: Simulium Family PSYCHODIDJE: Phlebotomus - Family CULICIDJE: Culex-Aedes-Anopheles Family TABANIDJE: Tabanus-Hrematopota-Chrysops-Pangonia Sub~Order C y cl 0 r r hap h a - Family SARCOPHAGIDJE: Sarcophaga-Wohlfahrtia Family CESTRIDJE: Gastrophilus - <Estrus - Hypoderma - Dermatobia...Family MUSCIDJE Sub-Family Muscinre: Musca Sub-Family Calliphorinre: Lncilia-Calliphora-Microcalliphora -ChryS()myia~Cochliomyia. Calliphorine myiasis in sheep. Screw-worms in cattle and other animals. Sub-Family Stomoxinre: Stomoxys-Lyperosia Sub-Family Glossininre: Glossina ApPENDIX: Pupipara Family HIPPOBOSCl!?JE: Order HEMIPTERA Cimex-Ornithocoris Order ANOPLURA Cordylobia Hippobosca-Melophagus-Pseudolynchia g Sub-Order Malloph a g a Menopon- Eomenacanthus-Lipeurus-Goniocotes - Goniodes -Columbicola- BovicOla-Trichodectes-Heterodoxus-Feli- <;ola. Pediculosis iii poultry

3 ClONTENTS xv PAGES Sub-Order Siphunculata Hrematopinus-Lino~nathus. Pediculosis in domesticated mammals Order SIPHONAPTERA - Super-Family Parasitoidea Family DERMANYSSIDiE: Dermanyssus-Liponyssus Super-Family Trombidoidea Fpmily TROMBIDIIDiE: Trombicula-Neoschon~astia Super-Family Tarsonemoidea - Family PEDICULOIDIDiE: Pediculoides Super-Family Demodicoidea Family DEMODICIDiE: Demodex 341'-344 Ctenocephalides-Ceratophyllus-Pulex-Echidnopha~a CLASS ARACHNIDA Order ACARInA Super-Family Ixodoidea Family ARGASIDiE: Ar~as Family lxodidie: Ixodes. Tick paralysis. Boophilus-Mar~aropus Hyalomma-Rhipicephalus-Hremaphysalis- Dermacentor- Rhipicentor-Amblyomma-Aponomma. Ticks as parasites Super-Family Sarcoptoidea Family SARCOPTIDiE: Sarcoptes - Cnemidocoptes - Notredres Psoroptes-Chorioptes-Otodectes Family CYTOLEICHIDiE: Cytoleichus-Laminosioptes P CLASS PENTASTOMIDA Family POROCEPHALIDiE: Lin~uatula-Porocephalus HOST PARASITE LIST - ALPHABETICAL INDEX

4 334 ARTHROPOD PARASITES and rubbish removed and burnt. Cracks and crevices can be well sprayed with carbon tetrachloride or paraffin emulsion (p. 343) and then closed up by painting with hot tar. Order ANOPLURA This order includes the biting and sucking lice. They are small, wingless insects with short legs and antennre. The body is flattened dorso-ventrally: The lice live as permanent ectoparasites on mammals and birds. The females attach their eggs to the hairs or feathers of the host and the young lice resemble the adult. Sub-Order MALLOPHAGA This group contains the biting lice, which are characterised by their broad, flat heads, usually rounded anteriorly, and the mandibulate mouthparts which are situated on the ventral side of the head. All the bird lice and also some mammalian lice belong to this group. The most common poultry lice are the following: Menopon gallinre (Linne, 1758) (syn. M.pallidium), the" shaft louse," is pale yellow in colour. Male 1'71 mm., female 2'04 mm. long. The thoracic and abdominal segments have each one dorsal row of bristles. Occurs on fowls, according to Piaget also on ducks and pigeons, and moves about rapidly. The eggs are laid in clusters on the feathers. M. phreostomum (Nitzsch, 1866) occurs on the peacock. Eomenacanthus stramineus (Nitzsch, 1874) (syn. Menopon biseriatum) is the yellow" body louse," occurring on the skin of those parts of the body which are not densely feathered like the breast, thighs and around the anus. Male 2 8 mm., female 3'3 mm. long. The abdominal segments have each two dorsal rows ofbristles. The eggs have characteristic filaments on the anterior half of the shell and on the operculum, and are laid in dusters on the feathers near the skin. Occurs on the fowl, turkey, peacock and Japanese pheasant, and is especially harmful to small chicks. Lipeurus heterographus Nitzsch, 1866, the" head louse," occurs on the skin and feathers of the head and neck. Male 2'43 mm., female 2 6 mm. long. In the male the first segment of the antenna is long and thick, bearing a posterior process. The abdomen is elongate in the male and barrel-shaped in the female, with dark-brown lateral tergal plates. The eggs are laid singly on the feathers. Occurs on fowls and partridges. It is a dangerous parasite of chicks.

5 SUB-ORDER MALLOPHAGA L. caponis Linne, 1758, the "wing louse," is a slender, elongate louse which occurs on the under-side of the. large wing feathers and moves about very little. It occurs on fowls and pheasants. FIG COMMON FOWL LICE. (ORIGINAL.) A, Eomenacanthus stramineus; B, Goniocotes gigas; C, G. hologaster; D, Lipeurus heterographus; E, Menopon gallinte; F, Lipeurus caponis. Goniocotes gigas Taschenberg, 1842,.is a large louse occurring on the body and feathers ofthe fowl. Male 3'2 mm., female 5 mm. long.

6 ARTHROPOD PARASITES G. holo~aster Nitzsch, 1838, the " fluff louse," occurs in the fluff at the bases of the feathers. It is a small louse; the male is I mm. long and the female 1 6 mm. The body is broad and the head short and wide. Occurs on fowls, pheasants and pigeons. Goniodes melea~ridis (Linne, 1758) is a common louse of the turkey, and Columbicola columbre (Linne, 1758) (=Lipeurus baculus Nitzsch) occurs on domestic and wild pigeons. + FIG Eomenacanthus stramineus, EGO ATl'ACHED TO FEATHER. (ORIGINAL.) FIG A, Columbicola columbdi; B, Coniodes meleagridis. (ORIGINAL.) The common biting lice of domestic mammals are: Bovicola bovis (Linne, 1758) (=Trichodectes scalaris) on cattle. B. equi (Linne, 1758) (=Trichodectes parumpilosus) on equines. B. ovis (Linne, 1758) (=Trichodectes spluerocephalus) on sheep. B. caprre (Gurlt, 1843) (= Trichodectes climax) on goats. B. painei (Kellogg and Nakayama, 1914) on goats. B. limbatus (Gervais, 1847) on angora goats. Trichodectes canis (de Geer, 1778) (=T. latus) on dogs. Heterodoxus lon~itarsus (Piaget, 1880) on dogs, kangaroos and wallabies. Felicola subrostrata Nitzsch, 1838, on cats. Life-Cycle and Habits.-The eggs are attached to the hairs or feathers ofthe host and require the warmth ofthe body to hatch. Under suitable

7 SUB-ORDER MALLOPHAGA 337 conditions hatching occurs after S-8 days and the young lice moult three to five times, according to the species, before the adult stage is reached after 2-3 weeks. The lice cannot exist off their host for more than a few days, but they rarely leave their host spontaneously. The infection is therefore spread mainly during close contact of the hosts. The Mallophaga feed on epidermal scales, bits of feathers; or hairs and exudations of the skin. Blood has been found in,their alimentary canals on several occasions and Ries* found Rickettsias in Eomenacanthus stramineus. The blood may have been ingested from small FIG LICE OF THE HORSE. (ORIGINAL.) wounds on the animal. A, Bovicola equi,. B, HtEmatopinus asini. Kothin,t however, considers that certain species ofmallophaga are able to draw blood from the unbroken skin and that they are not as harmless as is generally believed. PEDICULOSIS IN POULTRY All poultry lice are biting lice and the most important are the " head louse" and the " body louse" on young chicks, which may kill their hosts. A few lice are not significant, but under suitable conditions their numbers may increase rapidly. They irritate their hosts so that these are restless 'and neither feed nor sleep well. The egg yield decreases and the plumage of the birds may become damaged. Control.-If possible the lice should be killed without disturbing the birds, and this is best done by painting the perches in the fowl-house with strong tobacco extract containing 40 per cent. nicotine, using about 400 gm. for every So metres (! lb. for 100 feet). The fowl-house should be closed at the back, but only partly closed in front, so that the fumes will not be too strong for the birds. All the birds should sleep in the building on the following two nights. The warmth oftheir bodies causes * Centr.j. Bact., I, Orig., 121 (1/2): t Zool.Anz., 56 (9/10):

8 ARTHROPOD PARASITES the nicotine. to evaporate and to kill the lice. Most or all eggs are alsd killed, but a second treatment may be necessary 10 days later. For dusting birds to kill lice a small quantity of sodium fluoride or sodium fluosilicate is placed between the feathers on various parts of the body. A good dusting-powder can also be made bymixing three tarts petrol (benzine) and one part carbolic acid with a sufficient amount of plaster of paris to absorb the liquid. If birds are dipped, this should be done in the morning ofa warm day and a 0'7 per cent. solution ofsodium fluoride is used. In order to increase the effect 1 per cent. flowers of sulphur and about 0'3 per cent. soap may be added. - Dust baths of fine dust,.c to which one-fifth part'flowers of siilpnur is added, have the effect of suffocating" the lice and are valuable aids:in controlling these parasites. Head lice on young chicks can 'be Killed by the application of any bland oil or soft fat. The biting lice of mammals are treated like the sucking lice. Sub-Order SIP.HUNCULA'fA The sucking lice are flattened dorso-ventrally, oval in shape, and have a distinct head., thorax and abdomen. The head is usually conical FIG CATTLE LICE. (ORIGINAL.) A, Bovicola bo~is j B, Hf2matopinus eurysternus j C, Linognathus vituli. and pointed anteriorly and the mouth parts are hidden within the head. c The legs are strong and bear powerful claws. Eyes are absent in the family Htematopinidte, to which the common sucking lice of domestic animals belong. These are: c Hrematopinus asini (Linne, 1755), -the sucking louse of equines.

9 SUB-ORDER SIPHUNCULATA 339 H. suis (Linne, 1758), the very large louse of pigs. H. eurysternus (Nitzsch, 1818), the" short-nosed" cattle louse, with a relatively short head and broad thorax and abdomen. FIG SHEEP LICE. (ORIGINAL.) A, Bovicola ovi.; B, Linognathus pedalis; C, L. africanus. Linognathus ovillus (Neumann, 1907), the body louse or "blue louse" of sheep, occurs in New Zealand, Australia and Scotland. Its head is much longer than wide and also longer than the thorax. L. vituli (Linne, 1758), the " long-nosed" cattle louse, which has an elongate head and body. L.africanus Kellogg and Paine, 1911, the Mrican "blue louse" of sheep.' L~ pedalis (Osborn, 1896), the "foot louse" of sheep. The head is as wide as long and not longer than the thorax. This louse occurs on the legs and feet of the sheep FIG. 238,-Hdimatopi,!us suis, FEMALE. where there is no wool. (ORIGINAL.) L. stenopsis (Burmeister, 1838) on goats. L. setosus (v. Olfers, 1816) (=L. pilijerus) on dogs and foxes.

10 340 ARTHROPOD PARASITES Life-Cycle.-The eggs are yellowish in colour and have an operculum at the upper pole. They are attached to the hairs of the host and hatch in days or even longer. The young louse passes through several ecdyses and reaches the adult stage in 2-3 weeks. The infection is spread. by close contact ofthe hosts,. since the lice do not leave their hosts spontaneously and cannot live long without them. In the case ofhorses, 'lice may be spread by curry-combs, brushes, blankets, saddles and harness transferred from one horse to another.. PEDICULOSIS IN DOMESTIC MAMMA~S Symptoms.-The biting as well as the sucking. lice cause irritation, which results in scratching, rubbing and biting, and loss of condition on the part of the host. Scratching may produce wounds or bruises on the animal, while in sheep the wool is damaged and it is also soiled by the freces of the lice. The coat becomes rough and shaggy, and in bad cases the hair becomes matted together. The skin turns dry,and scaly, so that large scabs or crusts may form, resembling lesions of mange. The'animals ~re restless; they do not feed well and their reduced condition may make them susceptible to other diseases. In the case of calves, lousiness leads to much licking, and since the hair is loose, hairballs readily form in the stomach. The foot louse of sheep is found most frequently around the dew-claws, and severe infections. may produce lameness. Htematopinus suis may spread swine fever by passing from a dead pig to healthy ones. -. Pediculosis is seen especially in winter in animals with a long winter coat and when they suffer from cold and insufficient feeding. Diagnosis is easily made by finding,the lice, especially when the animal is standing in the sunlight. Treatment and Prophylaxis.-The best method of treatment for lice is dipping in a carbolic (I per cent.) or nicotine (0'06 per cent.) dip. Arsenical dips kill some lice, but are not always effective;'cattle dipped regularly for ticks in arsenical dips may suffer badly from lice, but these can be killed by adding a carbolic dip to the arsenical solution. One dipping is not sufficient, since the eggs are not killed. In warm weather two dippings with an interval of 14 days will suffice, but in cool weather three dippings or an interval of 20 days may be necessary in the case of sucking lice, as they develop slowly. For treatment of sucking lice on foxes Hanson recommends the local application 'of 2 per cent. cresol, repeated after days. In heavy infections the foxes should be dipped on a warm day in the same solution

11 PEDICULOSIS IN DOMESTIC MAMMALS 341 made lukewarm, then one minute later in lukewarm soapy water and then dried. The snout should be covered to prevent aspiration of fluid when the head is dipped. Although practically all animals can be dipped in warm weather, this cannot be' done in the cold winter when lice are particularly frequent, and they should therefore be dipped in autumn if any lice are present. For winter treatment sodium fluoride can be used to destroy biting lice. Derris powder, pyrethrum or 'powdered naphthalin will keep lice in check, but will not eradicate them. Oils like paraffin oil, raw linseed oil and crankcase oil, applied with a hard brush, are effective and can be a.pplied to some animals, which must then be kept out ofthe sun for a day or two; but most oils act as depilatories on horses. FIG DOG LICE. (ORIGINAL.) A, Trichodectes canis j B, Heterodoxus longitarsus j C, Linognathus setosus. In the case of pigs, a bag wetted with oil and tied around a,slanting scratching-pole' will usually be sufficient to control 'lice. While the, animals are being treated, the buildings as well as implements, such as blankets, curry-combs and brushes, should be cleaned and disinfected. If the eggs of lice become detached with hairs from the host, they may hatch out under suitable conditions after 3 weeks or longer, and premises which have been occupied by infected animals may retain the infection for about a month. Order SIPHONAPTERA 1.. The fleas are wingless insects with laterally compressed, bodies, about 1'5-4 mm.long. The chitinous covering is thick and dark btown. Compound eyes are absent, but some species have large or small simple eyes.